A conventional clamping die comprises a pair of die members mounted on a platen with one of the die members being reciprocally mounted thereon whereby the die members may be clamped together to retain a tube therebetween. Prior to such clamping, a workman normally holds the tube in position within a die cavity formed in one of the members. Failure to precisely maintain the tube in position prior to clamping of the die members together could result in tube deformation and potential damage to the die members. The tube is bent by rotating the platen, subsequent to the clamping of the tube between the die members.